As a kind of a semiconductor device, a NAND type flash memory device having a three-dimensional structure has been known. In manufacturing the NAND type flash memory device having the three-dimensional structure, an etching is performed on a multi-layer film formed by providing a silicon oxide film and a silicon nitride film alternately so as to form a deep hole in the multi-layer film. U.S. Patent Application Publication No. 2013/0059450 discloses such an etching.
Specifically, U.S. Patent Application Publication No. 2013/0059450 discloses a method of etching a multi-layer film by exposing a processing target object having a mask on the multi-layer film to plasma of a processing gas.
A processing target object to be etched may include a first region having a multi-layer film formed by providing a silicon oxide film and a silicon nitride film alternately, and a second region having a single silicon oxide film. It is required to form spaces such as holes in both the first and second regions by perform an etching on the processing target object. As a processing gas capable of etching both the first and second regions, a processing gas including a hydrofluorocarbon gas is exemplified.